syslog
21Oct/110

NetMob 2011

Posted by Salvatore Scellato

Last week I was in (the other) Cambridge, attending the "Second conference on the Analysis of Mobile Phone Datasets and Networks", or NetMob, held at the MIT Media Lab together with SocialCom 2011. NetMob provides an interesting format: there is only one track of short contributed talks, with the possibility to present recent results or results submitted elsewhere.  Speakers have about 10-12 minutes to present their work and then there is plenty of time to discuss ideas network with other people over 2 days. I gave two talks: one of our research on the effect of geographic distance on online social networks and another on our recent work on universal patterns in urban human mobility.

The unifying theme of the workshop is the analysis of mobile phone datasets: as people user mobile devices more and to do more things, these datasets help us to understand complex processes such as spread of information, human mobility, the usage of urban geography and so on. Indeed, the range of talks presented at the workshop was impressive and fascinating, spanning between two main points: the first day focused more on studying user mobility, while the second day featured works on social behaviour.

Among the most innovative works during the first day there was a talk by people at MIT & Berkeley on using mobile phone CDRs to make sense of urban roads, proposing to use a the Gini coefficient to measure the diversity of individual traffic carried by each street. Individual user mobility was the main theme of several talks: I particularly liked one on the seasonal patterns of user movements, presented by Northeastern University researchers, and one by a large team led by Vincent Blondel on exploring the spatio-temporal properties of human mobility and the regular home-work routine of many users. Laszlo Barabasi gave an invited talk on mobility and predictability, presenting much of his last work and trying to connect the statistical properties of human mobility to the performance limits of many related applications that rely on user regularity. Finally, AT&T Labs presented their results on why it is impossible to anonymize location data.

The second day featured works on the social properties of mobile phone communication between users. Researchers at CMU presented their results on quantifying how social influence might compel users to adopt some products by using randomization techniques. Another interesting talk by a a joint team UC3M and Telefonica presented how time allocation in social networks has strong constraint that are likely to affect and be affect by the social structure itself: well-connected hubs have a lower importance on information transmission than less connected users, with important consequences on many dynamic social processes. Sandy Pentland have another invited talk, offering a wide overview of how mobile devices are changing the technological landscape with their ubiquitous sensing capabilities. Another interesting talk discussed the economic value of mobile location data, presenting scenarios user actions can be monetized and profit shared among different service providers.

Overall NetMob provided an insightful venue for discussions and potential collaborations, always revolving around the idea that as mobile devices become more and more ubiquitous they will offer new fascinating research opportunities.

Many more details about all the talks in the book of abstracts.

 

28Sep/110

IBM TCG Visit and Cambridge Networks Network

Posted by Jon Crowcroft

The last couple of days were busy - IBM visited en masse and their Technical consulting group of around 50 people showed up (in CMS) to talk about   various interesting topics - for me, the best one was a talk about financial service industry regulatory controls through risk data sharing (via a third party - a sort of nuclear test ban treaty assurance service) - very neat - lots of other good topics - Rolls Royce were also there - amusingly, IBM complimented Rolls on their reliable history (compared with the Software Industry) - i didn't feel it fair to mention the RB211 or the recent A380 shattered turbine:)

 

More locally crucual was the kickoff meeting of the Cambridge Networks Network - see http://www.cnn.group.cam.ac.uk/ for more info - the

This kickoff was to setup a cross group, grass roots movement to join up various people in systems biology, brain mapping, economics, eplidemiology (including plant sciences) and others to share common knowledge and methods/techniques for studying complex networked systems with interesting (e.g. emergent) phenomena - the kickoff was amibitious with talked from 5 people supposed to be 10 mins each (averaging 20 mins:)

 

some ideas i thought of while listening

 

1. weak ties (long links) in modular systems (social nets, the brain, the internet) serve the same purpose as random perturbations (like mutation) does in optimisation tools (like Genetic Algorithms or Simulated Annealing) - to get you out of local minima:- most GAs work by cross-over which implements parallel search in local areas of a fitness landscape (since similar genes share / cross over/breed and are succesful or not similarly) - I wonder if there is any literature on how graphs have a small (but non zero) fraction of "escape routes" from the highly interconnected/modular/cliqueish structure of a small world are slightyly more robust than purely hierarchical modular ones???

 

2nd thought was about epidemics (and economics) - the Vickers report on the banking sectore is basically quarantining domestic banks (building socieities) from the high risk (prostitution and drug user/gambling/casino) banking sector. on the other hand, sharing information problemly (see Efficient Markets) would also work (see IBM work above)

 

The difference is that a structural regulation is much easier to implement than a big bang transparent information regime. maybe we do one now, the other later - who knows?

 

The talk on Citrus Blight in Miami lemon trees was fun - reminded me plants (genetically) are a lot easier than animals (c.f. fluphone:)

 

The map of spread of the blight looked really like the map of the nuclear tests recently shown on youtube (see

for that (esp. for Anil:)

 

One nice name check was the work on neural structures and VLSI that showed Rent's Law applies to both - cute (but should we add weak ties to our multicore systems - one for Steve Furber maybe?)

 

Anyhow, this looks like a very good (young, active, enthusiastic, smart) initiative - they will be having a bi-weekly seminar series starting pretty soon - probably coordinated with the statslab's networking series....

(for people too young to recall, Rolls Royce actually went bankrupt in the 1970s trying to make carbon fiber turbine blades work - in the end, a government bailout fixed it, and they are ok - the problem they hit was the fibers in the original blades weren't knit in enough different directions - a prob,lem shared with the fiberglass bodywork o nthe Reliant Scimitar (and robin) which would shatter under fairly light impact into lots of dangeous shards. The solution is to sew 3 dimensions of fiber (much more expensve/complex, but immesnly strong, but also tunable for different flexibility in any given dimension) into the matrix - the recent A380 engine problem wasnt design, but manufacturing process...

15Jul/110

Socio-spatial properties of online social networks

Posted by Salvatore Scellato

Some social scientists have suggested that the advent of fast long-distance travel and cheap online communication tools might have caused the "death of distance": as described by Frances Cairncross, the world appears shrinking as individuals connect and interact with each other regardless of the geographic distances which separates them. Unfortunately, the lack of reliable geographic data about large-scale social networks has hampered research on this specific problem.

However, the recent growing popularity of location-based services such as Foursquare and Gowalla has unlocked large-scale access to where people live and who their friends are, making possible to understand how distance and friendship ties relate to each other.

In a recent paper which will appear at the upcoming ICWSM 2011 conference we study the socio-spatial properties arising between users of three large-scale online location-based social networks. We discuss how distance still matters: individuals tend to create social ties with people living nearby much more likely than with persons further away, even though strong heterogeneities still appear across different users.

30May/112

Place-Friends: designing a link prediction system for location-based services

Posted by Salvatore Scellato

Online social networks often deploy friend recommending systems, so that new users can be discovered and new social connections can be created. Since these service have easily millions of users, recommending friends potentially involves searching a huge prediction space: this is why platforms such as Facebook, LinkedIn and Twitter merely focus their prediction efforts on friends-of-friends, that is, on users that are only 2 hops away in the social network, sharing at least a common friend. Extending prediction efforts beyond this social circle is simply not worth it.

017/365 areyoucheckedin?

Nonetheless, in location-based social networks there is an unprecedented source of potential promising candidates for recommending new friends: the places where user check-in at.  In a recent paper which will appear at the upcoming ACM SIGKDD 2011 conference we address the problem of designing a link prediction system which exploits the properties of the places that users visit.

4Apr/115

20th International World Wide Web Conference – WWW 2011

Posted by Salvatore Scellato

I am just back from Hyderabad, in India, where I attended the 20th International World Wide Web Conference, also known as WWW 2011, to present our work on tracking geographic social cascades to improve video delivery.  This conference, organised as usual by the International World Wide Web Conference Committee (IW3C2),  represents the annual opportunity for the international community to discuss and debate the evolution of the Web, providing a mixture of academic and industrial content.

The word cloud shows pretty well the main themes of the conference this year, which heavily revolved around two large pivotal aspects: "social" and "search". Interestingly, there was not any attempt of merging the two things together, as Aardvark tried last year. Not surprisingly, "networks" are still popular in the community, and "Twitter" still enjoys a lot of interest, even though this may change with their new controversial Terms Of Service, which are likely to hamper social media data harvesting.

Overall it is a fairly big conference, with 2 initial days of workshops, tutorial and panels and then 3 days with 81 research papers. Also, there were three world-known personalities such as Dr. Abdul Kalam, Sir Tim Berners-Lee and Christos Papadimitriou that gave a keynote each. I will give a brief summary of the main research themes, with pointers to the most interesting papers. However, it was physically impossible to attend all the research sessions, as they were often happening simultaneously: you can find much more information on the conference website and on the official proceedings.